The present invention relates generally to electronically controlled freight train brakes and, more particularly, to the use of microprocessor controlled electronic valves to perform all brake pipe signal interpretation and relay functions and all brake cylinder pressure application and release functions of conventional pneumatic freight brake control valves.
The present invention contemplates using microprocessor controlled electronic valves, such as solenoid valves, to perform the brake pipe signal interpretation and relay functions as well as the brake cylinder pressure application and release functions of conventional pneumatic freight brake control valves, such as ABD, ABDW or ABDX.
Generally, the concept of electronic emulation of pneumatic control valves has been openly discussed by those of skill in the art and other interested persons at public meetings on electronic brakes sponsored by the Association of American Railroads.
Using electronic transducers to measure brake pipe and brake cylinder pressures, a microprocessor on cars within a train can monitor changes in the trainline brake pipe pressure and respond to such pressure changes by controlling valves which supply or exhaust brake pipe pressure to reinforce the pressure changes and by controlling valves which supply or exhaust brake cylinder pressure in proper accord with increases and decreases in the brake pipe pressure. The basic concept is to duplicate electronically the primary functions performed by conventional pneumatic control valves, including brake cylinder pressure control and brake pipe signal reinforcement for both quick service and accelerated release. With such emulation capability, cars equipped with Electronically Controlled Pneumatic (ECP) brakes, having an on-board electrical power supply or storage device, could be operated either in trains with electrically controlled brakes or in trains operated with pneumatic brakes. Such valves could, in theory, be freely intermixed with pneumatically equipped cars in any train and operated using standard pneumatic control signals.